Means for protecting countersunk screw-heads.



G. H. HOLM. MEANS FOR PROTECTING COUNTBRSUNK SCREW HEADS. APPLICATIONFILED FEB-12, lfll fl.

1 1 05,658, Patented Aug. 4, 1914.

DULHL Z0 I v Ca dera @1 4 wzw/ A 1 GUSTAVE I-I. HOLM, 0F BRIDGEPORT,CONNECTICUT.

MEANS FOR PROTECTING COUNTERSUNK SCREW-HEADS.

Specification of Letters Patent.

Patented An". 41, 1 9141!.

AppIication filed February 12, 1912. Serial No. 677,106.

To all whomit may concern:

Be it known that I, GUSTAVE H. HoLM, citizen of the United States, andresident of Bridgeport, in the county of Fan-field and State ofConnecticut, have invented certain new and useful Improvements in Meansfor Protecting Countersunk Screw-Heads, of which the following is aspecification.

This invention relates to means for protecting countersunk holes forscrew heads, to prevent the same from becoming filled with dirt, as forinstance those used 1n clamping jaws for securing work upon a rotarytable of machine tools.

Heretofore conside 'able trouble and 1nconvenience has been experiencedin the adjustment of screws as used for securing the clamping jaws upontables of machine tools, when it became necessary to adjust such jaws,for the reason that the holes surrounding the head of the screws wouldbe filled with chips and dirt, and would first have to be picked outbefore a wrench could be placed upon the screw for releasing the same.

It is therefore, the purpose of my invention to provide a covering meanswhereby the space or hole surrounding the heads of screws will beprotected against foreign matters such as the chips and dust from theoperation of a machine, or for other reasons, and to so design andconstruct said means, that the said screw head will at all times be freeand ready for the attachment of an operating wrench for the tighteningor loosening of the screw.

lVith these and other objects in View the invention consists in theconstruction and novel combination of parts hereinafter fully described,illustrated in the accompanying drawings, and pointed out in the claimshereto appended, it being understood that various changes in the form,proportion, size and minor details of construction within the scope ofthe claims may be resorted to without departure from the spirit orsacrificing any of the advantages of the inven tion.

Similar characters of reference denote like or corresponding partsthroughout the several figures of the accompanying drawings, and uponwhich,

Figure 1, shows a front perspective View of a part of a machine tool,including the frame, tool heads, rotary table, and clamping jaws to thecountersunk screw holes of which my invention is shown applied. F ig. 2,is a top plan view of one of said clamping jaws with screw andprotecting means attached. Fig. 3, is a central vertical longi-' tudinalsection through the said jaw and covering means and illustrating theapplication of. a wrench to one of the screws thereof. Fig. 4;, is adetached plan view of an open spring ring forming a shoulder for myprotecting device, and, Fig. 5, is a top plan view of a cap or washerwhich constitutes the inclosing member for a screw head socket as willlater be described.

Referring in detail to the characters of reference marked upon thedrawing 10 rcprcsents a rotary work carrying table forming a part of amachine tool. 11 a cylindrical body carried thereon and constituting thework that is being operated upon by the tools mounted in the tool heads12 and 13. Inmachines of this class the work to be operated upon isusually of a cylindrical character and is secured to the table by meansof the clamping jaws 14L adjustably mounted in the radial slots 15 ofthe table. Each of these jaws is secured to the table by means of a pairof clamping screws 16 and 17 that freely pass through the end portionsof the jaws and the said slots and en gage a slidable nut adjustablymounted in the T of the slot and adapted to be moved in or out by themovement of the aw when the screws are loose. These jaws may be arrangedto engage either the inside or outside of a cylindrical body in a mannerto secure the same in position to be opc'ated upon by the tools of theheads referred to.

The two screws in each jaw are substantially alike in construction, butby reason of the particular form and relative thickness of the two endportions of the jaw, one of the screws is necessarily made longer thanthe other, but is designed to be operated in the same manner, by meansof a suitable attachablc Wrench 18 which is set down into the socket forthe screw head in order to engage and turn the latter. The head of thescrew as shown is square and includes an annular shoulder 1!) that isseated in the bottom of the hole or socket 20 in order to afford asuitable grip upon the jaw. My improved means for protcctii'ig thesescrew head sockets includes a roui'ulcap 21. shown in detail in Fig. 5having a square hole therein which'is of a proper size and shape toreceive the head ofthe screw while the outer circumference and shape ofthe cap is made to freely fit the diameter of the-socket so as to insurea free vertical movement of the .capalong thehead of the screw andwithinits socket. A small spiral spring 22 is seated in the socket of the jawaround the head of the screw between the bottom of the. socket and thesaid cap, the tendency of said spring being to normally hold the capin-an upper position as shown in Fig. 3 in connection with the. longerscrew. I pro vide-a shoulder against which this cap is normally seatedas shown in the drawings, in the form of an. expandable, open wirespring 23 that is set into an internal annular groove 2st formed.adjacent to the outer edge of the screw head socket. This device can bereadily set in placev as-shown in Figs. 2 and3 by first compressing thespring and can likewise be easily removed should it be necessary atanytime toremove the screw or for any other reason to get at the insideof the socket. This. .cap is free to move up and downby the action of awrench and the spring when it is necessary to operate the.

screw, and on the other hand would benor: mally set against. the ringina manner to positively prevent any dust ordirt from getting down inthesocket. The little quantity of dirt orchips which might perhapscollect in the annulargroove stilleXist-ing withap plicantsforniforprotecting means, would be very slight and could be. readily brushed orblown out. It will, of course, be apparent that the construction of thehead-of the screw and the inclcsures, for the same as shown in thedrawings are identical ,andtherefore the same reference. numerals areused to apply to both. For the. purposeof. illustration, however, in F3, we have shown a wrench applied to theshorter screw, to illustrate theinclosingcap shoved down and the spring beneath it compressed.

lVhile my improved screw protecting means is shown anddescribed asbeingapplied to jaws for machine ;tools, yet it will be apparent that itcan be used in other,

places to equal advantage, and therefore 1 do not wish to be hunted inits use.

Having thus described my invention what I claim and desire to secure byLetters Patent is 1. The combination with a member having acountersunkscrew-head hole'and an annular shoulder formed around theinside of the outeredge. of the hole, a screw mounted in the hole, amovable cap for inclosing the outer end of the hole and having anopening therethrough to surround the head of the screw, and a spring fornormally holding ing acountersunk hole, containing an annular grooveformedaround the inside of the outer edge of the :hole, of a screwmounted.

in the hole; a detachable spring ring to fit in-saidzgroove, a movableoapior inclosing the: space of the hole surroundingthe head of thescrew, and a spring for normally holding the. cap out against the saidring,

but adapted toper-mit the cap to be shoved in for the. attachment or" awrench to the screw-head.-

41. The eonibi-nationwith a member having a countersunk screw head holewith an annnlar groove formed around the:.inside. hereo'li',..- of ,ascrew having a head ot.

a lesser diameterthan the hole,- ring-ito fit: 1n uSalCl. groove, 2.cap. mov.-

ably ITIQUDtGdvT/lilhll'l the holeand haying an. opening to receivethegsaid screw head-there in, ;and;a spiral spring within the holeandseated between the; bottom thereof. and-the sa d cap for normallyforclngthecap out-,1 Y ward,

Signed at Bridgeport in.-the;county of F airfield anclf-State ofOonnecticutthis3rd day of February A. DJ, 1912.

GUSTAVE H; HOLM.

l Vitnesses JOH W; BRAY, Harm L. OVIATT.

Copies of this patent may ,be obtained for'five cents eachbyaddressing@1162 Commissioner of Eatencs, Washington, D. 0.?

